The invention relates generally to medical monitoring systems, and more particularly to a non-invasive glucose monitoring system and method.
Certain conditions in diabetics lead to insufficient production of insulin, or render the cells incapable of recognizing or detecting the insulin produced. Moreover, this may lead to the person experiencing improper regulation of insulin produced by their body. In any of these conditions, it may be desirable to acquire information about the glucose level in blood of the person so that measures may be taken to prevent further deterioration of the condition.
Most glucose monitoring techniques have been predominantly invasive. For example, glucose monitoring using blood usually requires extraction of blood from the body of the subject. Although urine glucose monitoring is non-invasive, the presence of glucose in the urine typically does not accurately reflect how high or low the blood glucose concentration is. Furthermore, urine glucose measurements lag behind the blood glucose concentration by about 20 to 30 minutes, making it practically unusable for detecting surges in blood glucose levels.
Attempts have been made to monitor glucose non-invasively by utilizing near-infrared spectroscopy on the skin of the subject. These techniques rely on the scattered, absorbed or transmitted radiation to determine glucose levels. However, the variables associated with the skin (such as thickness, texture, and so forth) contribute to the variable reflection and refraction of light, thereby preventing accurate and reliable non-invasive measurement of blood glucose concentration. Furthermore, skin also causes large specular reflectance, further contributing to these problems. Similarly, changes in skin texture or temperature over time may also alter the measurement readings. In addition, the presence of multiple analytes, like water, that absorb in the near-infrared region confound the measurements and make it difficult to produce a reliable signal from the skin.
Thus, there is a need for a system and method to make effective measurements of analytes, such as glucose levels, in human tissue in a non-invasive manner.